The present invention is directed to an improved electronic starter for fluorescent lamps, and more particularly to a solid state starter circuit which will replace conventional glow starters without requiring a special ballast.
The glow starters conventionally used with fluorescent lamps have numerous disadvantages. For example, such starters require a long time to warm up and to glow after the power switch is turned on, and this is particularly a problem in cold weather. In addition, such starters also cause interference with radios and other communication devices due to the sparking noises generated during operation. In attempts to overcome these problems various types of non-glowing electronic starters have been developed in the past, but they have been unfit for direct connection to the circuit wiring present in existing fluorescent lamps. Furthermore, the use of such starters has been limited to small lamps of six to ten watts. Such prior non-glowing electronic starters have required an inductor and/or a capacitor with a large capacity in proportion to the lamp power because they required a special ballast transformer, Triac, and an LC oscillator circuit. Because such prior art devices were incompatible both in size and in circuit connections with conventional lamps using glow starters, if it was desired to use such devices it was necessary to limit their use to small lamps and to provide separate connections for them.
Some non-glowing electronic starters were able to provide rapid starting of fluorescent lamps through the use of harmonic oscillations. However, such devices shorten the life of the lamp filament and the high cost of such devices inhibited wide usage.